A display device, such as a TFT-LCD (Thin Film Transistor Liquid Crystal Display), scans gate lines row by row to gate each row of the gate lines row by row, then outputs data voltages to each subpixel through data lines, and finally displays one frame image. In a prior art, when a plurality of frames of images are continuously displayed, a full-screen image is usually updated at a specific frequency, for example, 60 Hz. However, in this way, in the case that a part or all of the displayed image does not change in consecutive multi-frames, multiple full-screen updates increase a power consumption of the display device.